Cross browser testing is the process of testing the web application frontend on many different browsers and versions thereof. Web browsers run their home-grown engines to generate user interfaces based on HTML, CSS, and JS source code.
|Gecko||Firefox (and derivatives like SeaMonkey & Waterfox)|
|Blink||Chromium (and derivatives like Chrome, Edge, Vivaldi, Brave & Opera)|
|WebKit||Safari (and all iOS browsers)|
All in all, given the different combinations of browsers (& versions), operating systems (& versions), screen sizes, and resolutions, the number of combinations is staggeringly high; and supporting the most popular permutations is vital for businesses.